Treatment of crude oil for refinery (in particular crude oil which has complicated rheological structure) is a process that determines profitability of the whole petrochemical industry.
Upon availability of treatment (pre-processing of crude oil before feeding to the reactor for refining) the subsequent processing of oil raw materials requires much less time, thus increasing the productivity of the process.
Pre-processing of crude oil is performed with the following purposes:                desalting and dehydration,        viscosity reduction of oil and petroleum products (improvement of rheological properties),        removing sulfur and sulfur compounds from crude oil.        
It was developed some methods of pre-processing of crude oil focused on partial modifications in the structure of hydrocarbon links in order to, in addition to the above, as far as possible to increase the yield of light ends on the earliest stages.
There is a method (RU 2158288, 27 Oct. 2000), under which crude oil before feeding to the column for refinery is exposed to complex hydro mechanical and acoustic treatment in the rotary-pulsating acoustic apparatus in a certain range of velocities in the gap between rotor and stator. As a result of changes in the disperse oil state, the yield of oil distillate fractions increases. Disadvantage of the method is a great energy and metal consumption.
There is a method (U.S. Pat. No. 4,323,448, 6 Apr. 1982), under which mechanical activation of hydrocarbons is carried out by passing them through a disintegrator with exposure of impacts at a given frequency.
There is a method (RU 2122457, 27 Nov. 1998), under which hydrocarbon compounds in a liquid form are placed in an artificial gravity field and supply of mechanical energy to the liquid is provided by means of mechanical elements. Disadvantage of these methods is a great energy and metal consumption.
There is a method of cavitation effect in the processing of different liquids, including for intensification of processing of hydrocarbon raw materials.
Method of patent (KZ 14129, 15 Mar. 2004) is characterized by the fact that, when petroleum passes through cavitator, formation and growth of cavitation bubbles and their subsequent collapse occur, accompanied by shock waves disrupting structure of heavy molecules of hydrocarbons, including paraffin and asphalt-resinous substances.
Gas temperature inside a cavitation bubble at the end of collapse becomes very high, because the process happens so quickly that it's no time to establish heat exchange between contents of the bubble and surrounding liquid. Hot gas contacting heavy molecules, heats them up to the temperature at which strength of links between atoms decreases and molecules are disintegrated to more simple compounds. At disintegration of paraffin molecules more simple hydrocarbons, light fractions, are formed (paraffin content is reduced due to disintegration of its molecules). Asphalt-resinous substances content decreases due to their dissolution by the formed light fractions.
However, using of petroleum raw materials of different chemical and fractional composition, different viscosity and other physical and chemical characteristics, for some of them the cavitation mechanism can not be realized and in this case the mechanical destruction of these raw materials may not be carried out.